of midland



Reissued Apr; 23, 1929.

' UNITED STATES (PA NT: OFFICE.

WILLIAM Inna Arm .rosnrzr w. mm or menu, moment, assicnons we ran DOW onrarrchr. coMrANY, or MIDFLAND, 'mrcnrean, A oonrona'rron or mcnman.

I PROCESS FOR MAKING ANILINE QED OTHERiABgLAMIN ES.

1q -mi 0riginal !io. 1,807,824, dated November 23, 1526, Serial Ho. 7,133,fl1ed'lerbruary 5, 1925. i v Application for rcissue filedllayf. 1927. Serial No. 190,038.

v i The resent improvements relate more par ticular y to a process for making arylammes by reacting between the corresponding halogenated aromatic hydrocarbon and ammonia.

'5 In 1893, Merz and Paschkowezky (J. f. prakt. Chem. ($48,465) announced the production of traces of aniline through the interaction of bromobenzine, ammonium carbonate, and dry soda limevwhen heated under pressure for 10 many hours at 360-370. In the German Patent, 204, 951 (1907) the claim is made that an 80 per cent yield in aniiine'may be obtained by useof certain copper salts as catalysts upon chlorobenzene and aqueous ammonia when heated together under pressure for twenty hours at 180-2009 and still more recently, A. J. Quick (Am. Chem. Soc. 42, 1033 (1920)) has stated that cuprous salts are the effective agents in this reaction whereas cupric salts, when held in oxidized form, and even metallic copper itself, are Without action.

. As a result of the foregoing reactions and l of a careful study of the influence of various substances upon the possible catalysts, we have determined that cuprous salts are vastly more efiective. than cupric salts and that neither copper nor any other metal, when present alone as such, has any effect as 'a catalyst in this reaction between chlorobenzene and aqueous ammonia; I We have, however, made thefurther important discovery that copper when added to a reaction mixture of halogenated benzene and aqueous ammonia containing acuprous salt definitel promotes the catalytic effect of such salt an if suflicient' copper be present to bring about a reduction of a cupric salt to cuprous state, then, the latter may be equally I well used thus in combination with copper.

indicated with the detail modifications heredescribed and particularly- 7 inaftei" fully poifited out in theclaims, thefollowing description setting forth but several of the various ways in which the principle of the invention may be used. r 1

Accordingly, by the introduction into the By way of comparis n with the best results heretofore obtainabl 1n a reaction of the gen'. eral character in question, it may be stated that 1f in a reaction mixture ofrchlorobenzene and aqueous ammonia, containing 0.1 to 0.2 mole of cuprous chloride, metallic copper be added, the reaction will be speeded up to such an entent that practically complete conversion 1s obtained Within a few hours at 200 degrees (3.; while at a slightly higher temperature, the conversion is complete in less than one hour. The following is given as a specific example of the procedure involved in carrying out our improved method or process using monochlorobenzcne and aqueous ammonia with cuprous chloride and copper as catalyst and promoter, respectively, viz 1 7 Chlorobenzene is mixed with a 25 per cent aqueous ammonia solution in such amounts as to furnish about five moles of anhydrous ammonia-to one mole of the chlorobenzene. Th s mixture is then charged with 0.1 mole ofcuprous chloride and passed through '2 tubular system provided with copper heated to-the desired temperature, which may range from 150250"G.- The same result may he 8 obtained by heating this mixture in large copper 'autoclaves or autoclaves of inert material lined or'provided with copper. The efliuent liquors aredischargedinto closed vessels for removal, first, of the ammonia, then of the aniline,'and usual way. The, general reaction involved may be rep resented by the following equation,=viz

finally the phenol, n the.

Under ordinary conditions the proportion of phenol to anilmels about as 1 :20. With somewhat higher concentrations ofammonia,

this can be made to. approach the proportion F1 of 1:50 but beyond that it is not feasible, as. at present advised, to proceedp As will be noted in the foregoing descrip- .tion, our process is most advantageously carried out 1n a continuous tubular heating-sysouaun umol. v

- tions show thathalides other than'cuprous cuprous chloride, but alsoby a study of the. action of halides or salts of those metals halides actually serve. to retard the catalytic ,efl'ect' of copper salts. This has been made *evident not only'by a study of the action of ammonium chloride, sodium chloride, and

similar chlorides, when added to the reaction mixture of chlorobenzene, ammonia. and

above as well as below copper in the electroinotive series of metals when added to this same reaction mixture. Previous attempts to employ the general type of reaction herein in' question involve the entry into the solution of a molecule of ammonium chloride simultaneously with each molecule of aniline that is formed; consequently as the conversion of holgenated benzene proceeds, the ammonium chloride building up necessarily retards more and more the effect of the catalyst itself, so that complete conversion was never beforeobtainable. In our improved process on the contrary, the advantageous effect of the copper outweighs the disadvantageous effect 0 the ammonium chloride which thus builds up during the process. Es pecially is this true when air is present in the system chlorobenzene-ammonia-cuprous chloride and copper. In other words, the

copper in the presence of ammonia combines with free oxygen with the production of cuprous oxide and thus nullifies any retardant action on the part of the ammonium halide through simple interaction of the lat-v ter with the cuprous oxide, more and more of such oxide, which is the effective catalyst, .being" currently introduced into the system. The reaction that occurs may be represented by the following equation When airis entirely absent from the system, the addition of a small amount, 0.2 moles of cuprous oxide gives the same resultin serving to reduce the concentration of ammonium halides to a negligible factor. 'In'either case consideration of the quantity of cuprous chloride formed in process will be used to determine the quantity of the same catalyst required at the next stage.

We claim particularly to have discovered that with a maximum quantity of cuprous benzene hydrocarbons: (By ammonolysis we typify the same general type of; reaction known .as hydrolysis, ammonia. replacing water.) i 7 i In conclusion, it may. be stated that copper displays the sameeifect of a promoter to the cuprous salt catalyst in the reaction between aqueous ammonia and other poly-halogenated and substituted benzene hydrocarbons. In other words, it is to be understood that our im roved process is applicable not merely to am ine or phenylamine, C II .NH,, but to the production of the homologues of aniline or the various arylamines in general as illustrated'by the following examples, VIZ

l. Dichlorobenzene, C ILGl with ammonium cuprous chloride and copper, readily yields C HJNHQ phenylenediamine.

yields CH C H NH toluidine.

3. Chloronaphthalene, O H CI, similarly yields C H NH naphthylamine.

I 4. Chloroanthraquinone, C H.,O Cl, simi-- larly yields C H O NH amino-anthraquinone.

. Other modes of applying the principle 0 our invention may be em loyed instead of 2.011lorotoluene, (lH C H Cl, similarly" the one explained, change eing made as regards the method herein disclosed, provided the step or steps stated by any of the following claims or the equivalent of such stated 'stepor steps be employed.

We therefore particularly point out and distinctly claim as our invention 1. In a method of making an arylamine, the step which consists in reacting between'the corresponding halogenated aromatic hydrocarbon and ammonia in the presence of a copper compound and metallic copper.

2. In a method of making an arylamine, the step which consists in reacting between the corresponding halogenated aromatic hydrocarbon and ammonia in the presence of a cuprous compound and metallic copper.

'3. .In a method of making an arylamine the step which consists in reacting between the corresponding halogenated aromatic hydrocarbon and'ammonia in the presence of a cuprous oxide and metallic copper.

4. In a method of making aniline, they step which consists in reacting between monohalogenated benzene and ammonia in the presence of a. copper compound and metallic copper.

5. In a method of making aniline, the step which consistsin reacting-between chloro .benzene and ammonia in the presence of a cuprous compound and metallic copper.

Y 6. In a method ofmaking-aniline, the step "which consists in reacting between chlorobenzene and aqueous ammonia solution'in apormer to fivemoles of anhydrous ammonia, in the presence of a cuprous compound and metallic copper.

roximately the proportion of one mole of the zone a reaction mixture of. chlorobenzene and ture of chlorobenzene and ammonia, with an addition of a cuprous compound. 11. The method of promoting the effectiveness of a copper compound as a catalyst in a reaction of the character described involvwhich consists in heating a reaction mixture of mono-halogenated benzene and ammonia, with an addition of cuprous oxide.

14. In a method of making aniline, the step which consists in heating a reaction mixture of chlorobenzene and ammonia, with an ad dition of cuprous oxide.

15. In a method of making aniline, the step which consists in reacting between chlorobenzene and aqueous ammonia solution in approximately the proportion of one mole'of the former to five moles of anhydrous ammonia with the addition of from 0.1 to 0.2 mole of a cuprous compound.

16. In a method of making aniline, the step which consists in reacting between chlorobenzene and aqueous ammonia solution in approximately the pro ortion of one mole of the former to five mo es of anhydrous ammonia with the addition of from 0.1 to 0.2 mole of cuprous oxide.

17. In a method of making an. arylamine, the step which consists in passing through a heated zone a reaction mixture of the corresponding halogenated aromatic hydrocarbon and ammonia, with an addition of cuprous oxide.

18. In a method of making aniline, the step which consists in passing through a heated zone a reaction mixture of mono-halogenated benzene and ammonia, with an addi tion of cuprous oxide.

Signed by me this 7th day of May, 1927 WILLIAM J. HALE.

Signed by me this 25th day of April, 1927.

. JOSEPH W. BRITTON. 

